It more depends on how much brood you can save and how fast they can recover, more than the stores. They need to recover and produce enough winter bees for the colony to survive. The closer we get to Fall, the harder it is to do a cutout because of all the stores and the more bees that will be killed during the process.
You need to be extra careful and take your time to get as much of the brood (and queen) as possible. Put them in as small as possible hive configuration and let them build back up their strength.
When you say take all the stores, do you me for yourself? I would suggest feeding as much of the stores back to them as possible. If done correctly, you should be able to build them back up for winter.
As the season progresses, I usually raise my prices because of the added work involved, to the point that I try to convince people to wait until Spring. Early Spring removals are much much much easier as the stores have been reduced to a minimum.